1. Technical Field
The present invention relates to methods of superficially applying low-viscosity liquids onto given components. In particular, the invention relates to a method of coating on a low-viscosity, in-solution oil repellent obtained by dissolving a fluorine-based oil repellent resin in a highly volatile organic solvent.
2. Description of the Related Art
Forming coatings of oil-repellent resins, which primarily are fluoroplastic resins, on designated portions of mechanical devices to impart water-repellency or oil-repellency to those areas is conventional. Forming such coatings without restrictions has, however, proven difficult, in that various contrivances to do so have been brought about to date.
For example, methods of brush application, of spraying on with a sprayer, of dipping in a solution and subsequently drawing out and drying, of spin-coating, of transfer-printing, and of dripping a solution onto designated regions with a brush or like instrument are known. Furthermore, direct formation of an oil-repellent film onto the target surface by means of vacuum deposition or plasma polymerization has also been proposed.
Vacuum and other vapor-deposition techniques, however, necessitate large-scale equipment. Dip-coating and spin-coating are prohibitive of application to designated areas. With brush application, because the tip of the brush deforms, applying a material onto designated areas proves challenging. A particular problem with brush application is that the oil repellent solidifies due to evaporation of the solvent and clings to the brush in the vicinity of the tip, whereby the flexibility of the brush is compromised and at the same time clumps of the solidified oil repellent end up adhering to the target object, such that the applicability of this technique to precision components is especially problematic.
Japanese Unexamined Pat. App. Pub. No. 2004-289957 to Misu et al. discloses an ingenious method in which, using a pair of nozzles whose tips are closely adjacent, an in-solution oil repellent is on the one hand supplied from one of the nozzles while being aspirated through the other, whereby the oil repellent is applied locally with the nozzles being kept out of contact with the target object.